The goal of this program is to develop light scattering techniques for the non-invasive study of structure in fresh (i.e. unfixed) tissues. In these studies light scattering measurements are used to characterize corneas whose physiological conditions are carefully controlled. Theoretical light scattering techniques are used to calculate the scattering from the structures depicted in electron micrographs from various depths within the corneas. Comparison with the experimental light scattering data both tests the validity of these structures and determines the extent to which light scattering affords a technique for probing structure. Our previous studies have confirmed the usefulness of this methodology (Farrell, McCally and Tatham, J. Physiol., 233, 589-615 (1973)). During the coming year our attention will be focused on measuring the depth dependent scattering in near forward directions from swollen corneas. The measurements will be made using a new apparatus which will have been completed by the end of the current year. The scattering contribution from stromal cells will also be measured.